Sustainable Façades for the Indian Market Criteria, concepts, components, tools, and services

Across centuries, building forms and types have been adapted to local climatic conditions. Only in the 20th century did the development of the technology of mechanical air-conditioning allow the design of building envelopes independently of the conditions and parameters of the local setting. However, this development comes at a price. Not only are the operating and initial costs of such structures on the rise but the dependency on complex technology and the increasing need for raw materials are also the consequences. This problematic tendency can be observed across all metropolitan centres around the developing and developed world. During the last twenty years, increased population and productivity have led to unparalleled industrialization and urbanization in many regions of the planet. Corresponding increases also in human prosperity are intrinsically linked to greater demands for living space and comfort, which has resulted worldwide in limits of resource supply. Energy today is still supplied mainly from non-renewable fossil sources, which are constraints. As a result of the increasing demand and the limits of supply, an increasing number of societies are discovering the need for sustainability and the minimization of unnecessary resource consumption, as well as the optimization of efficiency.

Human endeavour and wellbeing are closely related to comfort levels. Sustainable buildings are characterised by the fact that they guarantee high levels of comfort with a minimal use of material and energy. In the realm of building, this trend, first and foremost, needs to consider a building's enclosure system - the façade. In the same period, a somewhat divergent tendency could be observed in Germany where it became more and more significant that building facades don't just look good, but also serve the need for durability and operation of a building. Thus building envelopes are the key for indoor comfort and operational expenditures. The façade not only is responsible for the cost related to the operation of the building's mechanical systems but can determine whether, or to what degree, a building needs such systems in the first place.

The façade needs to possess and deliver across its entire life span superior resource efficiency, which needs to be the result of energy and material efficiency not only in concepts and materials of the envelope but also in the development of highly efficient design, construction, and operational processes. Over the years - especially in Germany - not only highly sophisticated façade systems have been developed but also more intelligent and efficient design and construction methods. But what is essential to understand is the fact that facades need to be designed and operated differently according to global region, climate, and time in order to successfully minimize and optimize the above-mentioned aspects. In India the most important functions of the façade consist, above all, of ensuring sufficient weather-tightness and also solar protection. Moreover in our market-research we found out, that we had to reduce the complexity of our products and processes. We took all of that into consideration, when we adapted our products (windows, sliders and facades), tools (soft- and hardware) and consulting as well as training services to the Indian needs.

For instance we try to transfer our sixty years of project experience in many countries around the world to the Indian situation in our architectural advisory services. Sustainable facades require an overall optimisation of frame, glazing, shading and non-transparent areas. Daylight systems, on the other hand, have the role of evenly distributing the entering daylight within a room and optimizing the daylight quality. A façade which is really optimised for energy and comfort should be able to react to the comfort needs of the user and the changing outside conditions in such a way that the technical building equipment is only brought into play in extreme situations. Fundamentally, this means a building structure which is right for its location and use, in conjunction with an appropriate façade. Adaptable building envelope components are capable of reacting to non-continuous, changing external conditions that are in many instances predictable and can be calculated, such as the case with annual or diurnal swings in meteorological conditions (i.e., solar altitude angle) or the times of a building's operation. However, non-predictable weather and operational aspects should be included as well, such as variations in cloud cover and spontaneous presence of users. Sub-optimal operational procedures not only cause an enormous increase in operating cost but also result in non-acceptable interior comfort conditions. By this it is important to point out that the knowledge of users and/or operators of buildings, an aspect we may call operational competence, becomes of increasing significance. The most innovative building concept will inadvertently fail if it only performs in theory.